The use of composite materials in the design and manufacture of aircraft and spacecraft is becoming increasingly prevalent due to the low-weight and relatively high-strength properties achievable with those materials, among which fiber-reinforced polymer composites, such as carbon fiber reinforced polymers (CFRP), are especially preferred. An important issue with the use of fiber-reinforced polymer composite materials in modern aircraft production concerns the repair of such components; i.e. when those components are found to have a defect or if they sustain damage due to an inadvertent impact. Clearly, it will generally be preferable to repair a component having a small defect or minor damage rather than replace an entire component, especially for larger or more complex components.
Current techniques for repairing damaged CFRP components in the aircraft industry involve removing an affected area (e.g. a damaged area or a defective area) from the component and inserting a ply doubler. This has the notable disadvantage, however, that elongate or continuous reinforcing fibers of the component extending through the affected area are cut or severed. In order to achieve a corresponding load-carrying or load-transfer capability in this area, therefore, the repair is required to substantially reinforce the component in this area.